This document specifies the procedures, which may be used to
\nensure that implementations of IS-96-C\u00a0compatible
\nvariable-rate speech codecs meet recommended minimum performance
\nrequirements. This speech codec is the Service Option 1 described
\nin IS-96-C. The Service Option 1 speech codec is used to digitally
\nencode the speech signal for transmission at a variable data rate
\nof 8550, 4000, 2000, or 800 bps.<\/p>\n
Unlike some speech coding standards, IS-96-C does not specify a
\nbit-exact description of the speech coding system. The
\nspeech-coding algorithm is described in functional form, leaving
\nexact implementation details of the algorithm to the designer. It
\nis, therefore, not possible to test compatibility with the standard
\nby inputting certain test vectors to the speech codec and examining
\nthe output for exact replication of a reference vector. This
\ndocument describes a series of tests that may be used to test
\nconformance to the specification. These tests do not ensure that
\nthe codec operates satisfactorily under all possible input signals.
\nThe manufacturer shall ensure that its implementation operates in a
\nconsistent manner. These requirements test for minimum performance
\nlevels. The manufacturer should provide the highest performance
\npossible.<\/p>\n
Testing the codec is based on two classes of procedures:
\nobjective and subjective tests. Objective tests are based on actual
\nmeasurements on the speech codec function. Subjective tests are
\nbased on listening tests to judge overall speech quality. The
\npurpose of the testing is not only to ensure adequate performance
\nbetween one manufacturer's encoder and decoder but also that this
\nlevel of performance is maintained with operation between any
\npairing of manufacturers' encoders and decoders. This
\ninteroperability issue is a serious one. Any variation in
\nimplementing the exact standard shall be avoided if it cannot be
\nensured that minimum performance levels are met when
\ninter-operating with all other manufacturers' equipment meeting the
\nstandard. This standard provides a means for measuring performance
\nlevels while trying to ensure proper interoperation with other
\nmanufacturers' equipment.<\/p>\n
The issue of interoperability may only be definitively answered
\nby testing all combinations of encoder\/decoder pairings. With the
\nnumber of equipment manufacturers expected to supply equipment,
\nthis becomes a prohibitive task. The approach taken in this
\nstandard is to define an objective test on both the speech decoder
\nfunction and the encoder rate determination function to ensure that
\nits implementation closely follows that of the IS-96-C
\nspecification. This approach is designed to reduce performance
\nvariation exhibited by various implementations of the decoder and
\nrate determination functions. Because the complexity of the decoder
\nis not large, constraining the performance closely is not onerous.
\nIf all implementations of the decoder function provide essentially
\nsimilar results, then interoperation is more easily ensured with
\nvarious manufacturers' encoder implementations.<\/p>\n
The objective and subjective tests rely upon the use of a master
\ncodec. This is a floating-point implementation of IS-96-C written
\nin the C programming language. The master codec is described more
\nfully in 3.4. This software is used as part of the interoperability
\ntesting.<\/p>\n
By convention in this document, the Courier font is used to
\nindicate C language and other software constructs, such as file and
\nvariable names.<\/p>\n","protected":false},"excerpt":{"rendered":"
Recommended Minimum Performance Standard for Digital Cellular Spread Spectrum Speech Service Option 1<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2000<\/td>\n NA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":0,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-692165","1":"product","2":"type-product","3":"status-publish","5":"product_cat-tia","7":"first","8":"instock","9":"sold-individually","10":"shipping-taxable","11":"purchasable","12":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/692165","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=692165"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=692165"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=692165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}